Work vehicles, such as tractors and other agricultural vehicles, typically include an engine and a transmission, such as a power shift transmission (PST) or a continuously variable transmission (CVT), coupled to the engine. The engine and the transmission are often controlled by one or more electronic controller(s). For example, a transmission controller may be used to control the fluid pressure of the hydraulic fluid supplied to the various clutch actuators associated with the transmission clutches, which, in turn, controls the engagement and/or disengagement of the clutches.
When the transmission is fully engaged, the travel direction of the associated work vehicle may be deduced by determining which of the transmission clutches are engaged (i.e., based on the current clutch pattern for the transmission). However, when the transmission is not fully engaged (e.g., when shifting from park to the forward or reverse direction), conventional transmission controllers are not capable of determining the current travel direction of the work vehicle. As such, when a work vehicle is parked on the side of a hill or inclined surface and the operator commands that the vehicle be moved up the inclined surface, the transmission controller is not able to detect instances of the vehicle rolling back down the inclined surface as the transmission is being shifted. Accordingly, conventional work vehicles often experience undesirable “rollback” events when operating on an inclined surface.
Additionally, to detect the direction of travel of a work vehicle, more recent transmissions have been equipped with a bi-directional speed sensor. However, bi-directional speed sensors are typically quite expensive and, thus, their use within a work vehicle transmission is often undesirable.
Accordingly, an improved, cost-effective system and method for controlling the operation of a work vehicle transmission based on the detection of unintended vehicle motion, such as unintended rollback, would be welcomed in the technology.